| 1 | /* |
| 2 | * Emulation of Linux signals |
| 3 | * |
| 4 | * Copyright (c) 2003 Fabrice Bellard |
| 5 | * Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| 19 | */ |
| 20 | #include "qemu/osdep.h" |
| 21 | #include "qemu.h" |
| 22 | #include "user-internals.h" |
| 23 | #include "signal-common.h" |
| 24 | #include "linux-user/trace.h" |
| 25 | |
| 26 | struct target_user_regs_struct { |
| 27 | abi_ulong gpr[32]; |
| 28 | abi_ulong sa0; |
| 29 | abi_ulong lc0; |
| 30 | abi_ulong sa1; |
| 31 | abi_ulong lc1; |
| 32 | abi_ulong m0; |
| 33 | abi_ulong m1; |
| 34 | abi_ulong usr; |
| 35 | abi_ulong p3_0; |
| 36 | abi_ulong gp; |
| 37 | abi_ulong ugp; |
| 38 | abi_ulong pc; |
| 39 | abi_ulong cause; |
| 40 | abi_ulong badva; |
| 41 | abi_ulong cs0; |
| 42 | abi_ulong cs1; |
| 43 | abi_ulong pad1; /* pad to 48 words */ |
| 44 | }; |
| 45 | |
| 46 | QEMU_BUILD_BUG_ON(sizeof(struct target_user_regs_struct) != 48 * 4); |
| 47 | |
| 48 | struct target_sigcontext { |
| 49 | struct target_user_regs_struct sc_regs; |
| 50 | } QEMU_ALIGNED(8); |
| 51 | |
| 52 | struct target_ucontext { |
| 53 | unsigned long uc_flags; |
| 54 | target_ulong uc_link; /* target pointer */ |
| 55 | target_stack_t uc_stack; |
| 56 | struct target_sigcontext uc_mcontext; |
| 57 | target_sigset_t uc_sigmask; |
| 58 | }; |
| 59 | |
| 60 | struct target_rt_sigframe { |
| 61 | uint32_t tramp[2]; |
| 62 | struct target_siginfo info; |
| 63 | struct target_ucontext uc; |
| 64 | }; |
| 65 | |
| 66 | static abi_ulong get_sigframe(struct target_sigaction *ka, |
| 67 | CPUHexagonState *regs, size_t framesize) |
| 68 | { |
| 69 | abi_ulong sp = get_sp_from_cpustate(regs); |
| 70 | |
| 71 | /* This is the X/Open sanctioned signal stack switching. */ |
| 72 | sp = target_sigsp(sp, ka) - framesize; |
| 73 | |
| 74 | sp = QEMU_ALIGN_DOWN(sp, 8); |
| 75 | |
| 76 | return sp; |
| 77 | } |
| 78 | |
| 79 | static void setup_sigcontext(struct target_sigcontext *sc, CPUHexagonState *env) |
| 80 | { |
| 81 | abi_ulong preds = 0; |
| 82 | |
| 83 | for (int i = 0; i < 32; i++) { |
| 84 | __put_user(env->gpr[HEX_REG_R00 + i], &sc->sc_regs.gpr[i]); |
| 85 | } |
| 86 | __put_user(env->gpr[HEX_REG_SA0], &sc->sc_regs.sa0); |
| 87 | __put_user(env->gpr[HEX_REG_LC0], &sc->sc_regs.lc0); |
| 88 | __put_user(env->gpr[HEX_REG_SA1], &sc->sc_regs.sa1); |
| 89 | __put_user(env->gpr[HEX_REG_LC1], &sc->sc_regs.lc1); |
| 90 | __put_user(env->gpr[HEX_REG_M0], &sc->sc_regs.m0); |
| 91 | __put_user(env->gpr[HEX_REG_M1], &sc->sc_regs.m1); |
| 92 | __put_user(env->gpr[HEX_REG_USR], &sc->sc_regs.usr); |
| 93 | __put_user(env->gpr[HEX_REG_GP], &sc->sc_regs.gp); |
| 94 | __put_user(env->gpr[HEX_REG_UGP], &sc->sc_regs.ugp); |
| 95 | __put_user(env->gpr[HEX_REG_PC], &sc->sc_regs.pc); |
| 96 | |
| 97 | /* Consolidate predicates into p3_0 */ |
| 98 | for (int i = 0; i < NUM_PREGS; i++) { |
| 99 | preds |= (env->pred[i] & 0xff) << (i * 8); |
| 100 | } |
| 101 | __put_user(preds, &sc->sc_regs.p3_0); |
| 102 | |
| 103 | /* Set cause and badva to 0 - these are set by kernel on exceptions */ |
| 104 | __put_user(0, &sc->sc_regs.cause); |
| 105 | __put_user(0, &sc->sc_regs.badva); |
| 106 | |
| 107 | __put_user(env->gpr[HEX_REG_CS0], &sc->sc_regs.cs0); |
| 108 | __put_user(env->gpr[HEX_REG_CS1], &sc->sc_regs.cs1); |
| 109 | } |
| 110 | |
| 111 | static void setup_ucontext(struct target_ucontext *uc, |
| 112 | CPUHexagonState *env, target_sigset_t *set) |
| 113 | { |
| 114 | __put_user(0, &(uc->uc_flags)); |
| 115 | __put_user(0, &(uc->uc_link)); |
| 116 | |
| 117 | target_save_altstack(&uc->uc_stack, env); |
| 118 | |
| 119 | int i; |
| 120 | for (i = 0; i < TARGET_NSIG_WORDS; i++) { |
| 121 | __put_user(set->sig[i], &(uc->uc_sigmask.sig[i])); |
| 122 | } |
| 123 | |
| 124 | setup_sigcontext(&uc->uc_mcontext, env); |
| 125 | } |
| 126 | |
| 127 | static inline void install_sigtramp(uint32_t *tramp) |
| 128 | { |
| 129 | __put_user(0x7800d166, tramp + 0); /* { r6=#__NR_rt_sigreturn } */ |
| 130 | __put_user(0x5400c004, tramp + 1); /* { trap0(#1) } */ |
| 131 | } |
| 132 | |
| 133 | void setup_rt_frame(int sig, struct target_sigaction *ka, |
| 134 | target_siginfo_t *info, |
| 135 | target_sigset_t *set, CPUHexagonState *env) |
| 136 | { |
| 137 | abi_ulong frame_addr; |
| 138 | struct target_rt_sigframe *frame; |
| 139 | |
| 140 | frame_addr = get_sigframe(ka, env, sizeof(*frame)); |
| 141 | trace_user_setup_rt_frame(env, frame_addr); |
| 142 | |
| 143 | if (!lock_user_struct(VERIFY_WRITE, frame, frame_addr, 0)) { |
| 144 | goto badframe; |
| 145 | } |
| 146 | |
| 147 | setup_ucontext(&frame->uc, env, set); |
| 148 | frame->info = *info; |
| 149 | /* |
| 150 | * The on-stack signal trampoline is no longer executed; |
| 151 | * however, the libgcc signal frame unwinding code checks |
| 152 | * for the presence of these two numeric magic values. |
| 153 | */ |
| 154 | install_sigtramp(frame->tramp); |
| 155 | |
| 156 | env->gpr[HEX_REG_PC] = ka->_sa_handler; |
| 157 | env->gpr[HEX_REG_SP] = frame_addr; |
| 158 | env->gpr[HEX_REG_R00] = sig; |
| 159 | env->gpr[HEX_REG_R01] = |
| 160 | frame_addr + offsetof(struct target_rt_sigframe, info); |
| 161 | env->gpr[HEX_REG_R02] = |
| 162 | frame_addr + offsetof(struct target_rt_sigframe, uc); |
| 163 | env->gpr[HEX_REG_LR] = default_rt_sigreturn; |
| 164 | |
| 165 | return; |
| 166 | |
| 167 | badframe: |
| 168 | unlock_user_struct(frame, frame_addr, 1); |
| 169 | if (sig == TARGET_SIGSEGV) { |
| 170 | ka->_sa_handler = TARGET_SIG_DFL; |
| 171 | } |
| 172 | force_sig(TARGET_SIGSEGV); |
| 173 | } |
| 174 | |
| 175 | static void restore_sigcontext(CPUHexagonState *env, |
| 176 | struct target_sigcontext *sc) |
| 177 | { |
| 178 | abi_ulong preds; |
| 179 | |
| 180 | for (int i = 0; i < 32; i++) { |
| 181 | __get_user(env->gpr[HEX_REG_R00 + i], &sc->sc_regs.gpr[i]); |
| 182 | } |
| 183 | __get_user(env->gpr[HEX_REG_SA0], &sc->sc_regs.sa0); |
| 184 | __get_user(env->gpr[HEX_REG_LC0], &sc->sc_regs.lc0); |
| 185 | __get_user(env->gpr[HEX_REG_SA1], &sc->sc_regs.sa1); |
| 186 | __get_user(env->gpr[HEX_REG_LC1], &sc->sc_regs.lc1); |
| 187 | __get_user(env->gpr[HEX_REG_M0], &sc->sc_regs.m0); |
| 188 | __get_user(env->gpr[HEX_REG_M1], &sc->sc_regs.m1); |
| 189 | __get_user(env->gpr[HEX_REG_USR], &sc->sc_regs.usr); |
| 190 | __get_user(env->gpr[HEX_REG_GP], &sc->sc_regs.gp); |
| 191 | __get_user(env->gpr[HEX_REG_UGP], &sc->sc_regs.ugp); |
| 192 | __get_user(env->gpr[HEX_REG_PC], &sc->sc_regs.pc); |
| 193 | |
| 194 | /* Restore predicates from p3_0 */ |
| 195 | __get_user(preds, &sc->sc_regs.p3_0); |
| 196 | for (int i = 0; i < NUM_PREGS; i++) { |
| 197 | env->pred[i] = (preds >> (i * 8)) & 0xff; |
| 198 | } |
| 199 | |
| 200 | __get_user(env->gpr[HEX_REG_CS0], &sc->sc_regs.cs0); |
| 201 | __get_user(env->gpr[HEX_REG_CS1], &sc->sc_regs.cs1); |
| 202 | } |
| 203 | |
| 204 | static void restore_ucontext(CPUHexagonState *env, struct target_ucontext *uc) |
| 205 | { |
| 206 | sigset_t blocked; |
| 207 | target_sigset_t target_set; |
| 208 | int i; |
| 209 | |
| 210 | target_sigemptyset(&target_set); |
| 211 | for (i = 0; i < TARGET_NSIG_WORDS; i++) { |
| 212 | __get_user(target_set.sig[i], &(uc->uc_sigmask.sig[i])); |
| 213 | } |
| 214 | |
| 215 | target_to_host_sigset_internal(&blocked, &target_set); |
| 216 | set_sigmask(&blocked); |
| 217 | |
| 218 | restore_sigcontext(env, &uc->uc_mcontext); |
| 219 | } |
| 220 | |
| 221 | long do_rt_sigreturn(CPUHexagonState *env) |
| 222 | { |
| 223 | struct target_rt_sigframe *frame; |
| 224 | abi_ulong frame_addr; |
| 225 | |
| 226 | frame_addr = env->gpr[HEX_REG_SP]; |
| 227 | trace_user_do_sigreturn(env, frame_addr); |
| 228 | if (!lock_user_struct(VERIFY_READ, frame, frame_addr, 1)) { |
| 229 | goto badframe; |
| 230 | } |
| 231 | |
| 232 | restore_ucontext(env, &frame->uc); |
| 233 | target_restore_altstack(&frame->uc.uc_stack, env); |
| 234 | |
| 235 | unlock_user_struct(frame, frame_addr, 0); |
| 236 | return -QEMU_ESIGRETURN; |
| 237 | |
| 238 | badframe: |
| 239 | unlock_user_struct(frame, frame_addr, 0); |
| 240 | force_sig(TARGET_SIGSEGV); |
| 241 | return 0; |
| 242 | } |
| 243 | |
| 244 | void setup_sigtramp(abi_ulong sigtramp_page) |
| 245 | { |
| 246 | uint32_t *tramp = lock_user(VERIFY_WRITE, sigtramp_page, 4 * 2, 0); |
| 247 | assert(tramp != NULL); |
| 248 | |
| 249 | default_rt_sigreturn = sigtramp_page; |
| 250 | install_sigtramp(tramp); |
| 251 | |
| 252 | unlock_user(tramp, sigtramp_page, 4 * 2); |
| 253 | } |